How long will it take to get pregnant?
To get pregnant it is necessary to have sex around the time of the month when the woman is ovulating. The chance of getting pregnant can be affected by several factors related to both the man and the woman including: age, weight and whether either smoke or drink alcohol.
Fig 1. Proportion of women pregnant over 2 years
For a couple to be fertile, the woman needs to produce an egg from the ovary each month and her tubes must not have any blocks to the passage for egg and sperm and the man would not have problems producing sperm.
If a couple is fertile and trying to have a baby, most women (up to 85%) will get pregnant within a year if they are having sex regularly and not using contraception. Up to 95% will get pregnant within two years. These are averages, some women will get pregnant quickly and some will take longer.
Why pregnancy might not occur
Infertility can be the result of problems with the woman (40%), the man (40%) or both (10%) and in the remaining 10% of the population the cause is unknown.
Female problems preventing pregnancy
When a woman is born there are usually one million eggs in each ovary and these are the only eggs she will produce. Normally one egg will be released when she ovulates every month during her menstrual cycle, which is approximately 400-500 eggs over her lifetime. As a woman gets older the rest of the eggs disappear, break down or deteriorate and by the time she reaches menopause, there are no eggs left.
As a woman ages it takes longer to get pregnant, the chance of getting pregnant decreases and the quality or health of the eggs decreases too.
- At age 25 years, only 5% of women take more than a year to get pregnant
- Starting at about age 32 years, a woman’s chances of conceiving decrease gradually but significantly
- By age 35 years, 30% of women take more than a year to get pregnant
- From age 37 years, a woman’s fertility decline speeds up
- By age 40 years, fertility has fallen by half 
Women and their partners should ideally see a doctor for a check up if they are planning to have a baby. If a woman has been trying to get pregnant for more than a year she should see a doctor. If she is over 35 years old she should see a doctor if she has been trying for six months or more and if a woman is not having monthly periods she should see a doctor.
Ovulation is when an egg is released from a woman’s ovary, usually about two weeks before her next period. Hormones released from the brain and ovaries cause ovulation and this normally occurs every month.
For the next 24 hours after its release the woman can become pregnant if the egg comes in contact with a male’s sperm. Some of the reasons why ovulation may not happen are:
- Hormone problems: there are a number of hormone problems that can stop the egg growing in the ovary and if this happens usually a woman will not have a period every month – blood tests can help to work out if this is the problem
- Some of the hormonal imbalances may be caused by:
- Weight: women who are overweight or obese or those who are underweight (can have hormone imbalances that mean ovulation doesn’t happen regularly and therefore it can take longer to achieve a pregnancy
- Polycystic Ovary Syndrome: this condition causes the body to produce higher than normal amounts of male hormones– this may mean that the ovaries do not release an egg every month so periods/monthlies are irregular (many women with PCOS (40%) will get pregnant without medical help but some women do have trouble becoming pregnant)
There a number of things that can cause reduce the quality or health of a woman’s eggs and may reduce her chance of getting pregnant.
Some of these are:
- family history or genetics
- cancer treatment such as radiation or chemotherapy
Fallopian tube blockage
Fig. 2 Female reproductive organs
The fallopian tubes or tubes shown in Fig 2 connect the ovaries to the uterus If the tubes become blocked this may stop the sperm meeting the egg which prevents a woman becoming pregnant.
Common causes of blocked tubes are
- sexually transmitted infections e.g. pelvic inflammatory disease
Male problems preventing pregnancy
It is not just the age of the woman that’s important when trying to have a baby. The quality or health of a man’s sperm decreases with age. This means it will take longer for a woman to get pregnant or she may not be able to get pregnant at all without assisted reproductive technology (ART) such as IVF.
- If a woman is under 25 and her partner is under 25 it will usually take her 4-5 months to get pregnant
- If a woman is under 25 and her partner is over 40 it will take nearly 2 years for her to become pregnant
The amount of semen that a man produces and the ability of sperm to swim or move forward towards an egg continue to decrease between the ages of 20 and 80.
There are several problems that can occur with sperm that might affect the woman’s chance of getting pregnant. The sperm count (the number of sperm per ml of semen), sperm motility (the way the sperm moves or swims) and sperm shape can all impact on the chance of a woman becoming pregnant.
There are many factors that will affect the number and health of the sperm. These include:
- a history of sexually transmitted infections e.g. chlamydia
- certain medical, hormonal or genetic conditions
- alcohol (more than 2 drinks per day)
- being overweight
- some prescription medications
- cancer treatment
- Tube blockage: male tubes can also be blocked because of structural problems such as previous surgery or infections – this may result in sperm is not being able to meet and fertilise an egg
- Varicoceles: these are varicose or large veins in the scrotum which may also affect fertility
How to improve fertility
Some causes of infertility may require medical or surgical treatment while others are related to lifestyle. These are some of the things a couple can do to improve their fertility and chance of getting pregnant:
- Reach or maintain a healthy weight
- Eat a healthy and balanced diet
- Stop smoking cigarettes
- Stop smoking/using marijuana and other drugs
- Reduce or stop alcohol intake
- A woman can try and monitor her cycle and see if she notices any changes around ovulation (pain with ovulation, mucous discharge from vagina changes from thick and white to clear (like uncooked egg white ) and stretchy, which helps the sperm to swim more easily
- Use ovulation tests to help to recognise when the egg is being released
When to see a doctor about fertility?
A couple should see a doctor if they are trying to get pregnant and
- a woman does not have a periods or has irregular periods
- they have been trying for 12 months or more
- a woman is 35 or over and has been trying for 6 months
It is also important for women to have a pre-pregnancy check up to make sure she is in the best health possible before she gets pregnant.
What will the doctor do?
The doctor will ask questions about how long a woman has been trying to conceive and the couple’s medical history to help determine what test are required. Some common tests are:
- semen tests or other tests to check sperm count and quality
- blood tests for the woman to check her hormone levels and make sure ovulation occurring
- to check if tubes are blocked a woman may need a laparoscopy, special X-ray called HSG or ultrasound
What treatment is available for fertility problems?
There are a range of treatment options depending on the cause of the infertility.
For a woman
- If she has blocked tubes she may need surgery or assisted reproductive technology (ART) to get pregnant
- If she is not ovulating she may need to try and improve her lifestyle (no smoking or alcohol) and reduce her weight – if this does not work she may need hormone tablets to help her get pregnant
- If she has polycystic ovary syndrome (PCOS) she may need hormone tablets or other treatment (see PCOS section on fertility)
For a man
- If a man has sperm problems (low count, quality or motility) ART may be required
- If he is producing sperm but tubes are blocked ART may be required
- If he has hormone or other medical problems these conditions may require treatment
It’s not always possible to find the cause of infertility and in these cases IVF or other forms of ART may be the only option for a couple to become pregnant.
Assisted reproductive technology (ART)
This is a general term used to describe ways to achieve pregnancy artificially or partly artificially. There are many different ways to do this and in vitro fertilisation (IVF) is one of the most common methods. In IVF the sperm and the egg are taken from the man and the woman and fertilised outside the body. The fertilised egg is then implanted in the woman’s uterus and she hopefully becomes pregnant.
This web page is designed to be informative and educational. It is not intended to provide specific medical advice or replace advice from your health practitioner. The information above is based on current medical knowledge, evidence and practice as at August 2013.